Apparatus for measuring liquid flow

Abstract

In a housing two ultrasonic measuring transducers are arranged opposite of the two end faces of a test tube. The test tube providing a measuring section penetrates a separating wall and interconnects two distribution chambers of the housing. The fluid to be measured flows through the test tube and influences the transit time of the ultrasonic impulses released and received by the measuring transducers. The test tube provides a constant cross-section of metallic material along the length of the measuring section. The connection between the test tube and the separating wall consists of a nonmetallic material, thus preventing echoes which may penalize the measuring accuracy.

Having thus described the invention, what I claim as new and desire to be secured by Letters Patent is as follows: 
     
       1. In a measurement generator for determining the rate of flow of a fluid passing through a pipe system, said pipe system including a housing and a test tube of a predetermined length disposed within said housing, said test tube extending along a longitudinal direction, the fluid flow being determined by measuring the transit time of ultrasound pulses within the fluid flowing through said test tube, a sound pulse emitting transducer being disposed near one end of said test tube in a first distribution chamber, said sound pulse emitting transducer having a first sound-transfer area, a sound-pulse receiving transmitter being disposed near the other end of said test tube in a second distribution chamber, said sound-pulse receiving transducer having a second sound transfer area, at least one distribution chamber forming part of said housing, said test tube including metallic material having a cross-section remaining the same over the entire length of said test tube, a common divider wall having an opening and separating said distribution chambers from one another, said test tube passing through said opening, said transducers being disposed at a certain distance from the respective test tube ends, said test tube guiding the ultrasound pulses from said sound transfer area of said sound-pulse emitting transducer to said sound transfer area of said sound-pulse receiving transducer along an axis coinciding with the flow of said test tube, the improvement comprising non-metallic connecting means extending along and surrounding said test tube so as to connect portions near opposite ends thereof through said opening in said common dividing wall, said common dividing wall extending approximately at right angles to said longitudinal direction,   whereby any sound echoes bouncing off said common divided wall are reduced in intensity.   
     
     
       2. A generator according to claim 1, wherein aid nonmetallic connecting means includes a bushing which surrounds at least partially the length of the test tube.   
     
     
       3. A generator according to claim 2, wherein said bushing has a wall thickness which decreases on each side of a central portion of said bushing having a constant thickness. 
     
     
       4. A generator according to claim 2, wherein said bushing includes a tube concentric with said test tube, and having an inner diameter larger than the outer diameter of the test tube, an annular space formed between the two concentrically arranged tubes being filled with a material capable of providing a high degree of acoustical neutralization between the two tubes. 
     
     
       5. A generator according to claim 4, wherein said two distribution chambers are firmly positioned on both ends of said tube respectively. 
     
     
       6. A generator according to claim 4, wherein said material in said annular space includes vulcanized rubber. 
     
     
       7. A generator according to claim 1, further including a second housing, the other distribution chamber forming part of said second housing.